U.S. patent application Ser. Nos. 11/182,344 and 11/141,283 disclose an integrated beamforming array that may be denoted as a “wafer scale antenna module” in that the antennas, beamforming electronics such as phase-shifters or amplitude-shifters, and feed network may all be integrated with a wafer scale semiconductor substrate. In these wafer scale antenna modules, an RF signal to be transmitted is driven into the feed network, which may be a co-planar waveguide (CPW) network or any other suitable transmission network. Distributed amplifiers within the feed network provide high gain to the transmitted RF signal, which may then be phase-shifted and/or amplitude-shifted such that a resulting RF signal propagated from the antennas coupled to the feed network is steered in a desired direction. Alternatively, the distributed amplifiers within the transmission network may form a distributed oscillator as discussed in U.S. application Ser. No. 11/536,625, filed Sep. 28, 2006, the contents of which are incorporated by reference. A received RF signal from the antennas arrayed on the wafer scale semiconductor substrate may be similarly phase-shifted and/or amplitude-shifted as desired and driven using distributed amplification through the same feed network used for transmission or a separate receive network. Because the resulting beam steering is electronically controlled yet formed using conventional semiconductor processes, such wafer scale antenna modules offer low cost design yet achieve state of the art gain and beam steering performance. Moreover, because the attached IF or baseband processing stage sees a single RF port (for either transmission or reception), only a single analog-to-digital converter is necessary. In contrast, conventional beamforming systems perform their beam steering in the IF or baseband domain which thus requires multiple channels be maintained in these domains. For example, suppose the antenna array is controlled in quadrants such that a first quadrant is to have a first phase, a second quadrant to have a second phase, and so on. A baseband or IF beam steering system must then have four channels supported for these four phases, thereby requiring four analog-to-digital converters. At high data rates, such systems must then perform massively parallel analog-to-digital conversion, which is expensive or simply unachievable at high data rates.
A similar wafer scale approach is disclosed, for example, in U.S. Pat. No. 6,982,670, the contents of which are incorporated by reference. In this approach, the semiconductor substrate includes a plurality of integrated antenna circuits. Each integrated antenna circuit includes an oscillator coupled to one or more antennas. Thus, in such a wafer scale approach there is no need for the complication of a feed network with distributed amplification because the RF signal is being generated locally within each integrated antenna circuit. However, the integrated antenna circuits need to be synchronized to each other. This synchronization may occur through reception at each integrated antenna circuit of a synchronizing signal from an integrated waveguide such as disclosed in U.S. application Ser. No. 11/536,625, filed Sep. 28, 2006, the contents of which are incorporated by reference.
Regardless of whether a wafer scale antenna module is formed using an RF feed network with distributed amplification or an array of integrated antenna circuits having oscillators, the beamforming commands need to be distributed to the phase-shifters and/or amplitude shifters that are integrated into the semiconductor substrate. These commands may be distributed across the substrate using photolithography to form appropriate conductive traces, but such traces complicate the circuit layout and may interfere electromagnetically with other signal distributions. To avoid such complications, a command distribution scheme that may be denoted as a “coupling array mesh” was disclosed in U.S. Pat. No. 6,870,670 that may electromagnetically couple through, for example, the far field. However, a far field coupling requires an antenna array to receive the beamforming commands (and also synchronization signals in the case of an integrated antenna circuit WSAM embodiment).
Accordingly, there is a need in the art for improved wafer scale antenna module beamforming command distribution schemes.